1. Field of the Invention
The present general inventive concept relates to an audio reproduction apparatus, and more particularly, to an apparatus and method of reproducing a 7.1 channel sound, by which a sound encoded using 7.1 channels is reproduced, through a 5.1 channel speaker system.
2. Description of the Related Art
An audio reproduction apparatus typically provides a surround sound effect similar to a 5.1 channel system using only two speakers.
Technology related to the audio reproduction apparatus is disclosed in WO 99/49574 (PCT/AU99/00002 filed Jan. 6, 1999 entitled AUDIO SIGNAL PROCESSING METHOD AND APPARATUS).
Referring to FIG. 1, technology relating to a conventional audio reproduction apparatus denotes a down mixing technique in which a 5.1-channel surround sound is formed using only a 2-channel speaker. The down mixing technique comprises convolving input signals with impulse responses using head related transfer functions (HRTFs) to form two groups of convolved signals corresponding to two channels (i.e., a left channel 10 and a right channel 11) and adding the two groups of convolved signals that correspond to the two channels.
As illustrated in FIG. 1, input signals 2 including a left-front channel input signal, a right-front channel input signal, a center-front channel input signal, a left-surround channel input signal, a right-surround channel input signal, and a low frequency effect (LFE) channel input signal are convolved with corresponding impulse responses, respectively. Convolved signals are divided into a left channel and a right channel and are then output through a 2 channel speaker. Consequently, a 2 channel output signal is reproduced, such that the conventional audio reproducing apparatus forms a surround sound effect during which a sound is reproduced through a left speaker, a right speaker, a center speaker, a left-surround speaker, and a right surround speaker that are located around a listener.
However, since speakers in the conventional audio reproducing apparatus are typically located in front of the listener, the conventional audio reproducing system has a difficulty in accurately forming a virtual sound at a rear side of the listener.